21339511 has 2 divisors, whose sum is σ = 21339512. Its totient is φ = 21339510.

The previous prime is 21339509. The next prime is 21339529. The reversal of 21339511 is 11593312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21339511 - 2¹ = 21339509 is a prime.

Together with 21339509, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21339581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10669755 + 10669756.

It is an arithmetic number, because the mean of its divisors is an integer number (10669756).

Almost surely, 2^21339511 is an apocalyptic number.

21339511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21339511 is an equidigital number, since it uses as much as digits as its factorization.

21339511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 810, while the sum is 25.

The square root of 21339511 is about 4619.4708571437. The cubic root of 21339511 is about 277.3712781243.

The spelling of 21339511 in words is "twenty-one million, three hundred thirty-nine thousand, five hundred eleven".